Kindle
These remarkable sand structures are apparently made of nothing more than sand and water and are really stupendous. All I've ever managed are a few pail-and-shovel turrets.
Link 1, Link 2
(Thanks, Barry!)
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.